Several prior art patents describe methods for “activating fuel” in which a solution of gas and fuel is prepared, and such material is then combusted. Reference may be had, e.g., to U.S. Pat. No. 6,273,072 of Knapstein, U.S. Pat. No. 7,523,747 of Gachik et al.; U.S. Pat. No. 8,037,849 of Staroselsky, and the like. The entire disclosure of each of these United States patents is hereby incorporated by reference into this specification. However, the prior art methods are not very efficient. It is an object of this invention to provide a more efficient method for activating fuel and using it in a diesel engine.